127-weekly-contest-python

Author: BradyHu

solution/1005.Maximize Sum Of Array After K Negations/Solution.py

@@ -0,0 +1,22 @@
+class Solution:
+
+    def largestSumAfterKNegations(self, A: List[int], K: int) -> int:
+        m = float('inf')
+        ans = 0
+        fu = []
+        for num in A:
+            if num < 0:
+                fu.append(num)
+                m = min(m, -num)
+            else:
+                ans += num
+                m = min(m, num)
+        if K >= len(fu):
+            K -= len(fu)
+            ans -= sum(fu)
+            if K % 2 == 1:
+                ans -= 2 * m
+        else:
+            fu.sort()
+            ans = ans - sum(fu[:K]) + sum(fu[K:])
+        return ans

solution/1006.Clumsy Factorial/Solution.py

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+class Solution:
+
+    def clumsy(self, N: int) -> int:
+        s = ''
+        calc = ['*', '//', '+', '-']
+        i = 0
+        while N != 1:
+            s = s + str(N) + calc[i]
+            i += 1
+            i %= 4
+            N -= 1
+        s += '1'
+        return eval(s)

solution/1007.Minimum Domino Rotations For Equal Row/Solution.py

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+class Solution:
+
+    def minDominoRotations(self, A: List[int], B: List[int]) -> int:
+        a, b = A[0], B[0]
+        c, d = b, a
+        counta, countb = 0, 0
+        countc, countd = 1, 1
+        for ai, bi in zip(A[1:], B[1:]):
+            if ai == a:
+                pass
+            elif ai != a and bi == a:
+                counta += 1
+            else:
+                counta = -30000
+            if bi == b:
+                pass
+            elif bi != b and ai == b:
+                countb += 1
+            else:
+                countb = -30000
+            if ai == c:
+                pass
+            elif ai != c and bi == c:
+                countc += 1
+            else:
+                countc = -30000
+            if bi == d:
+                pass
+            elif bi != d and ai == d:
+                countd += 1
+            else:
+                countd = -30000
+        if counta < 0 and countb < 0 and countc < 0 and countd < 0:
+            return -1
+        else:
+            ans = 30000
+            for count in [counta, countb, countc, countd]:
+                if count >= 0:
+                    ans = min(ans, count)
+            return ans

solution/1008.Construct Binary Search Tree from Preorder Traversal/Solution.py

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+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+
+class Solution:
+
+    def bstFromPreorder(self, preorder: List[int]) -> TreeNode:
+        def buildtree(li):
+            if not li:
+                return
+            val = li[0]
+            if len(li) == 1:
+                root = TreeNode(val)
+            else:
+                l, r = [], []
+                for item in li[1:]:
+                    if item > val:
+                        r.append(item)
+                    else:
+                        l.append(item)
+                root = TreeNode(val)
+                root.left = buildtree(l)
+                root.right = buildtree(r)
+            return root
+        return buildtree(preorder)